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Engine Powered Generators | Components and Types of Generators

Wed, 01/10/2018 - 18:12

Know About Generators – Engine driven Generators

A generator is best described as a machine, which transforms mechanical energy into electrical energy through combustion of a fuel. Although most of the engine driven generators have been argued to be hazardous to the environment but they offer various advantages to the users in industries.

An engine generator set, is more commonly known as “Genset”. They are generally rated in horsepower or a torque, watts or Kilowatts. The main components of an engine driven generator include an engine, fuel supply mechanism, a constant engine speed regulator and a generator voltage regulator, cooling and exhaust systems, and lubrication system which have been described in detail in this article.

Generators usually use the following as fuel: gasoline, diesel, natural gas, propane, biodiesel, water, sewage gas or hydrogen. Generators of small size use gasoline (petrol) or diesel as a fuel, and the larger ones run on diesel, natural gas or propane. Some engines may also operate on diesel and gas simultaneously.

Components of an engine driven generator

Engine: In an engine driven generator, engine is the main component. It creates mechanical energy that gets converted into electricity. A generator engine's design and size determines the maximum power output it can create by running on a specific fuel or other power source

Fuel Mechanism – Fuel tank, Fuel pipes, Fuel filter etc: The entire system contains a tank for storage of fuel and fuel pipes connecting the tank and the engine. The fuel pump moves the fuel through the fuel pipes to the engine and a fuel filter helps filter any debris from the fuel before delivery to the engine. This ensures maximum efficiency and increase the durability of the engine. The fuel injector injects the fuel directly into the combustion chamber of the engine.

Alternator: The alternator consists of the stator and the rotor. A set of coils that conduct electricity is call a stator which is a stationary part, whereas a rotor moves to create a constantly rotating electromagnetic field around the stator.

Voltage Regulator: A voltage regulator is primarily used to regulate the voltage produced, which is suitable to the application or purpose of a generator.

Cooling and Exhaust System: Cooling system is required in a generator to avoid overheating or regulate the temperature when in use. An exhaust is required to dispel harmful gases emitted during operation of a generator. Generators often use a fan, coolant or both to control the temperature of the generator at work.

Lubricating System: Since generators comprise of many moving parts, they require regular oiling to ensure smooth functioning. The lubricating system in a generator helps in performing this function.

All these components play a crucial role in smooth functioning of a generator. The working principle of a generator is simple. The mechanical energy needed to turn the generator comes from the combustion of fuel through the fuel system. The coiled wires used, spin inside a magnetic field which causes electric current to flow in the wire. The voltage regulator helps to control amount of electric current that is produced. The coolant and exhaust system functioning in a generator helps regulating temperature and dispel gases respectively.

Types of generators

Generators are mainly of two types, Induction (Asynchronous) generator and Synchronous generator.

Induction Generators: An induction generator is also called as asynchronous generator. It is a type of Alternating Current (AC) electrical generator, which principally works similar to the working of induction motor to produce power. Induction generators are operated by mechanically turning their rotors faster than synchronous speed. They are generally very useful in applications such as mini hydro power plants, wind turbines, or in reducing high-pressure gas streams to lower pressure. Construction of induction generator is less complicated in comparison to synchronous generator as it does not require brushes and slip ring arrangement. Brushes are required in synchronous generator to supply DC voltage to the rotor for excitation

Synchronous Generators: In general, a synchronous generator is equipped with two parts, namely rotor and stator. The rotor part consists of field poles and stator part consists of armature conductors. The rotation of field poles induces an alternating voltage which results in electrical power generation.

Commercial electrical energy is mainly sourced by synchronous generators. Most common uses of these generators are to convert the mechanical power output of steam turbines, gas turbines, reciprocating engines and hydro turbines into electrical power for the grid which is mainly used in power plants.

These generators are designed to operate in complex and rigid processes of marine and industrial applications. They are highly efficient, reliable and certified by the most demanding Marine certifying agencies like DNV, ABS, BV, Lloyds. Common applications of these generators include diesel and gas driven reciprocating engines, prime and standby power and propulsion power for marine vessels. Diesel Generator Sets are generators that use diesel to run. These are commonly used as backup units for emergency power supply. They are available in both single and three-phase. Diesel engines in these gensets are sturdy and reliable. On the other hand, Natural Gas Generators, which use natural gas, work in a manner similar to other generators, however they are widely used and efficient means of generating power since it uses the most affordable and effective fuels among non-renewable resources for power generation.

But in comparison, a diesel generator is far more efficient. Also from a safety point of view it is more preferable, since diesel is less flammable than other fuel sources. New models of diesel gensets are less noisy. However, they are more expensive and may be bulky. A natural gas generator will use more fuel than a diesel generator.

Now, with the advent of biodiesel generators, disadvantages of a natural gas generator or a diesel generator can be discounted and they may become more of a buyer’s preference.

Engine driven generators are widely used in power generation, renewable energy, oil & gas, data storage & manufacturing industry and are mainly used for emergency power generation, backup power generation, wind power generation and hydroelectric power.

Top and well known manufacturers of generators offer different designs and features, suitable for all types of applications. Few of them are Onan, Marathon, Kato, Baldor, MTU and Caterpillar.

When it comes to choosing a generator, one must consider the following main deciding factors such as, understanding the main purpose the generator, its noise level, fuel tank capacity, price, kilowatt rating and efficiency, RPM and frequency, controls and related switchgear etc. They are available in different sizes and horsepower of engines.